Method and apparatus for die rolling



Patented Jan.. l?, 1928.

WILLAM P. EVITHEIROW, OF PTTSBURGH, PENNSYLVANIA, ASSIGNOR, BY MESNE AS-SGNll/IENTS, TO COLONIAL TRUST COMPANY, TRUSTEE, 0F

PITTSBURGH, PENNSYL VANIA, A CORPGRATION OF FENNSYLV'ANIA.

METHOD AND APPARATUS FOR DIE ROLLING.

Application filed July 12,

This invention relates broadly to die rolling', and certain featuresthereoi are applicable to die rolling in general, while other featuresthereof iind particular application in the die rolling of articleshaving a relatively short portion ot' `greater cross section thanadjacent portions, as, for example, a die rolled article having acollared portion.

ln metal rolling, it is general practice to drive one roll of the millfrom the power source, and to connect the other roll to the driven rollby means of gearing, the gears being connected to the rolls throughsuitable means, such as spindles, to permit adjustment of the rollsrelative to one another.

l have found that in setting up a pair ot die rolls preparatory torolling, particularly where it is desired to form an article which isbilaterally symmetrical with respect to the longitudinal axis, it ishighlypdesirable to set the driven roll in advance of the driving roll.The amount of setting; depends on a number of features, particularly thedraft, and the result of such setting' ahead is that the portions of thearticle which are formed in the two rolls coincide with one anotherexactly when the driven roll has been set ahead in the proper amount.`When such compensation is not made, the e'ect on the roll is as thoughthe portion formed in the driven roll had been slipped a short distancealong the length ci the article relative to the portion formed in thedriving roll. Obviously, far more satisfactory results can be attainedWhen such adjustment is made.

l believe that the necessity tor such adjustment arises because oi thetwist in the length oit the spindles and the deection of the pinionteeth when the mill is under load. All et these deflections are veryslight but would probably be sucient to give rise to the situation whichmy adjustment is inn tended to overcome, and such deilections would notshow up when operating the mill without passing any steel therethrough,or

it, for example, some very soit substance, such as plasticine, wererolled therein.

Another Jfeature et my invention which is particularly applicable to therolling ot articles havingI a relatively short portion et diderent crosssectional area than the adjacent portions, is the dimensioning1 ot amatrix portion in the driven roll for form 1 ing such portion et' thearticle as compared 1924. Serial No. 725,554.

with the corresponding matrix portion oi the driving roll, I have foundthat in rolling an article such as a collared shaft, it is desirable tomalte the matrix portion in the driven roll a little longer than thecorrespending matrix portion in the driving roll.

lt is a general theory in ordinary rolling that the force between therolls is entirely a force tending to separate the rolls and has nocomponent alongrl the line of the article being rolled. rlhis theory isadvanced because of the fact that in general rolling practice the barbeing fed to the rolls moves at a uniform speed. As the productIleaving` the rolls also moves at uniform speed, there can be noaccelerating torce.

Observation, however, shows that this is not true in die rolling, for insuch rolling a delivery speed of the article is dependent upon thevaryingpercentan'e ot reduction. Under these conditions` there must atvarying times exist between the die rolls a force in addition to thespreadingr torce, and one which is exerted along the axis ot 'the barbeing rolled. This force will either be in the direction of the articlebeing rolled or in opposition thereto dependingr on whether there is anenlargement or a reduction in the size ot the productat a particularinstance. This orce is the force required to accelerate the entire baron the delivery side ot the mill from its then velocity to a dita ferentvelocity imposed by the variation in cross section.

,lf believe that with variations in this Jforce alone the bar, thepressure between the pinion teeth will also vary. Stated in another way,the force required to rotate the driven roll and accomplish the wor-lrof rolling* will vary with changes in cross section, and there willtherefore be changes in the relative setting ot the driven roll ascompared with the driving roll. vllhis would require a continuousvariation in the amount the driven roll is set ahead of the driving;roll. but such variation cannot readily be effected when 'the mill is inoperation, and in any event, could not be accomplished without affectingall portions of the bar. l", therefore, provide a compensation for aparticular portion ot the article by varying the length of the conresponding portion ot the roll matrix from theoretical dimensions. Theabove theory, which ll believe to be a true explanation,

titl

lill

ltlli affords an understanding of the difficulties which are overcome bymy invention and will be found of value in determining which waycompensation is to be made and in what amount. However, I do not limitmyself to such theory, or to the correctness thereof.

In the accompanying drawings which show, for purposes of illustrationonly, a particular application of my invention,

' Figure l is a side elevation of a die rolled automobile drive shaft;

Figure 2 is a developed view of the driven roll for rolling the articleshown in Figure 1;

Figure 3 is a similar view showing the driving roll, and

Figure 4 is a cross sectional view through a pair of rolls constructedin accordance with the la out of Figures 2 and 3, and showing theirrelative setting.

The article shown in Figure l is an automobile propeller shaft S havinga collared portion C. Figure 4 shows a pair of rolls as set up in themill for rollin such articles, the direction of rotation glacingindicated by arrows. The lower roll 2 is the driving roll and the upperroll 3 is the driven roll. Figure 4 shows the relative set ting of thetwo rolls prior to starting up the mill and it will be observed fromthis figure that the various matrix portions of the roll 3 are slightlyangularly advanced with respect to the corresponding matrix portions ofthe driving roll 2. As above set out, this is a general setting ahead tocompensate for a twist in the spindles, deflecilgn of the pinion teethunder load and the In Figure 1, Z indicates the linear dimension of thecollared portion. Figure 2 shows that the corresponding matrix d in thedriven roll is longer than the corresponding matrix d for the drivingroll shown in Figure 3, or, to state it in another way, the leading edgee of the collar portion of the -matrix in the driven roll is in advanceof the corresponding leading edge e in the driving roll, as clearlyindicated in Figure 4. This advance of the leading edge is greater thanthe general setting ahead of the driven roll, the amount of compensationor additional settin ahead for this particular the difference in drabetween one portion of the article andk another, the cross sectionalarea of the sections on each side of the collar, the temperature andcomposition of the metal, etc.

A pair of rolls formed as illustrated in Figures 2 and 3 and set asdisclosed in Figure 4 in accordance with the present invention willresult in the rolling of an article such as shown invFigure 1, whereinthe por tions formed in the upper and lower rolls iptortion depen ing oncorrespond with one another throughout the length of the bar, regardlessof variations in cross section of the rolled work.

I thus overcome a great dii'iculty which has been experienced in dierolling by providing a mill having a driving and a driven roll, andsetting the driven roll ahead of the driving roll. I further provide fora supplemental setting ahead of various portions of the rolls in amountsgreater than the general setting ahead.

It will be understood that my broad invention contemplates the settingahead of the varying portions in accordance with the reduction at suchpoints, since apparently the amount of such setting ahead varies withthe reduction. This variation in the setting ahead effect acorresponding variation in the load between the pinion teeth. Actualapplication of the invention, however, shows that it is only when arelatively abrupt change in section is encountered that t e load variesin such an amount as to require a special compensation for a )articularroll portion, and that for general practice, the above disclosure ofsetting ahead all portions of the driven roll as compared with thedriving roll and only making a special compensation when an abruptchange of section is encountered, will give perfectly satisfactoryresults.

It will be apparent that I have shown and described only an illustrativeexample of my invention, and that it may be otherwise embodied andcarried out within the scope of the following claims.

I claim:

l. In the method of die rolling in a mill having a driving roll and adriven roll, the steps consist-ing'in vproviding co-operating matrixportions in the two rolls, placing the matrix portions of the drivenroll in advance ot the corresponding matrix portions of the driving rollin amounts corresponding to the amount of reduction in the mill by suchmatrix portions, passing a leader between such rolls and impressingsubstantially like configurations. by each roll on the leader,substantially as described.

2. In the method of die rolling an article having a relatively shortportion of different crosssectional area than the adjacent ortions ofthe article in a mill having a dliiving and a driven roll, the stepsconsisting in forming a matrix ortion of relatively greater length inthe riven roll than in the driving rc1 for rolling said ortion andpassing a leader between suc rolls, the matrix portions being so relatedas to impress su stantially like configurations on the leader,substantially as described.

3. In the method of die rolling with a pair of rolls havingcorresponding matrix portions, the steps consisting in varying thesetting of a. roll matrix portion in one roll ttl relative to thecorresponding roll matrix ortion in the other roll to compensate forvinertia forces set up in the article being produce an article whereinthe matrix portions form corresponding (article portions in properrelation to one another, substantially as described. v

4., A pair of die rolls adapted to produce an article havingsubstantially equal por-v tions lying adjacent one another on oppositesides of the median line of the blank, said die rolls having matrixportions therein adapted to produce such article portions, the matrixportion in one roll didering Jfrom the matrix portion in the other roll,such portions being so dimensioned as to impress substantially likeoppositely disposed configurations on the material being rolled,substantially as described.

5. pair of die rolls having generally similar matrices adapted tocooperate with one another and to form an article which is substantiallysymmetrical about the median* line of the article, said die rolls havingat least some matrix portions which correspond to one another but whichare of different length around the roll, substantially as descri-ned.,

d In the method of die rolling in a mill having a driving roll and adriven roll, the steps consisting in providing cooperating matrixportions in the two rolls, placing the matrix ortions of the driven rollin advance o the corresponding matrix portions ot the driving roll inamounts correspond- 'ing to the amount of reduction -in the mill by suchmatrix portions, corresponding matrix portions in the two rolls beingrelatively of such size and shape as to produce substantially likearticle portions, a matrix portion in the driven roll being placed inadvance of the corresponding portion Ain the driving roll in suchamounts that when a leader is passed between the rolls, the artionsticle ortions produced by such matrix por- Ilie substantially side byside, and passing a leader between the rolls, substantially asdescribed.

7. In the method of die rolling an article having a. relatively shortportion of different lthe rolls theyI substantially i cross-sectionalarea than the adjacent portions of the article in a mill having adriving and a driven roll, the steps consisting in setting the drivenroll ahead of the drivin@ roll, and also providing a matrix portion o?relatively greater length in the driven roll than in the driving rollfor rollin said portion, the matrix ortion in the riven roll being setahead o the corresponding matrix portion in the driving roll in suchamount, and being of such relative length that the matrix portions ofthe two rolls impress substantially like congurations on the materialbeing rolled, substantially as described.

8. In the method of die rolling to produce blanks which are bilaterallysymmetrical relative to the longitudinal `axes of the blanks, the stepsconsisting in providing a pair of rolls having matrix portions whichcorrespond to one another, but which are dissimilar one from the otherin at least certain portions thereof, a matrix portion in one rolldidering in dimensions from a corresponding matrix portion in the otherroll in such amount that when a leader is passed between the rolls theyare e'ect-ive :tor impressing substantially like congurations on thematerial being rolled, and passing a leader between the rolls,substantially as described.

9. In the method of die rolling to produce blanks which are bilaterallysymmetrical relative to the longitudinal axes of the blanks, the stepsconsisting in providing a pair 01E rolls having matrix portions which.correspond to onevanother, but which are dissimilar one from the otherin at least certain portions thereof, a matrix portion in one rolldiiering -in dimensionsffrom a corresponding matrix port-ion in theother roll in such amount that when a leader is passed between areeffective for impressing ke congurations on the material being rolled,setting one of the rolls ahead of the other in an amount suilicient tocause the article portions produced by cor- (lll responding matrixportions inthe two rolls v to lie side by side, and passing a leaderbetween the rolls, substantially as described. l In testimony whereof Ihave hereunto set wnlLIAM P. WITHEROW.

ioo

